Draft controller



qv.. 24, H936.. W. v MoRRas DRAFT CONTROLLER 2 shets-sheet 1 Filed NOV. 7, 1929 f-IZO IN VEN TOR. 'WLM-QL 74%@ 7 ATTORNEY.

'FIGURE-l 24, l936 w. L. MoRRls DRAFT CONTROLLER Filed Nov. 7, 1929 2 Sheets-Sheet 2 Patented Novn 24, i936 UNITED STATES PATENT OFFICE aocrssi I DRAFT coN'rnoLLEa William L. Morris, Chicago, IlL: Laura Bell Morris executrix of said William L. Morris,

deceased This invention relates in general to a controlling system employing a method of regulating the draft of a combustion furnace by raising and lowering the pressure under the grate instead of over the grate, and also in controlling the fire by the temperature of the escaping gases instead of regulation by the room temperature.

The principal objects of the invention are as follows; to prevent, when the fire is checked, any free atmospheric air from entering the chimney and reducing its temperature; to maintain a lower pressure in the furnace than in the air surrounding it and thereby preventing gases from leaking outward which happens when air is admitted between the furnace and chimney; to prevent the leakages that enter the ash pit from passing through the fuel when the fire is checked and retard the checking; to permit slight variations of pressure differences above and below the grates so that the rate of fuel burning can be accurately controlled; to carry into the furnace the gases formed in the magazine while the draft is on, and to prevent gases flowing into the furnace while it is checked; to prevent free air from passing by the magazine fuel and into the furnace when the fuel is low; to provide a single operator to control the draft and check valves so that each is operated alone throughout its range and is closed before the other is operated; to provide means for lightening the duty imposed upon the operator of the control valves; and in general to produce the structure herein shown and described.

The above and other features of novelty in the construction and operation of the invention will be apparent from the specification when considered in connection with the accompanying drawings which illustrate a preferred embodiment of the invention. 4.

In the drawings, Fig. 1 shows a vertical section through a hot air furnace having a magazine fuel feeder, a forced air circulating fan and a thermostat operated fire controller with its heat range setting device;

Fig. 2 shows a cross section of the smoke pipe and a sectional View through the lower portion of the thermostat case, and the draft valves and the connections as they appear backof the thermostat on the line 2 2 of Fig. 3;

Fig. 3 shows a side view of the smoke pipe and section through the electrical switch as indicated on the line 3-3 of Fig. 2;

Fig. 4 shows in detail the automatic self closing magazine air valve; and

Fig. 5 is a chart of thirteen different heat ranges.

Referring now more particularly to the drawings,'Fig. 1 shows the furnace parts as applied to a hot air furnace, which would be approximately the same for a hot water heater or a steam boiler excepting that the forced air circulating fan and its switch would not be used; in fact it is only used on a. limited number of hot air furnaces.

An ash pan or oor plate section I supports the furnace comprising an ash pit section 2 with an ash door 3 and an air nozzle 4, the ash pit section being cemented in its bearing on oor plate at joint 5. At the top of the ash pit are grates 6 which may be of any of the Various forms. A re pot section 1 is cemented to the ash pit section 2 at ajoint 8 and a charging section 9 rests in a cement bearing joint I0 at the top of the fire pot and has a re door I I and a magazine extension I2. A dome I3 for the furnace has a cement joint I4 with the top of the charging section 9 and on top of it a. radiator I5 is shown having a special top outlet I 6 so that the controller can be more clearly shown on the drawings above the furnace, the radiator having its cement joint I 1 much the same as for all sections.

An enclosing shell or casing I8 is attached to an outer flange of the floor plate section by bolts I9 and at its top has hot air discharge pipes 20, one of which is shown in Fig. l, anda cold air return pipe 2| which delivers air into the lower part of casing I8 through the fan flue 22.

A fan 23 in the cold air return is driven by an electric motor 24 which is bolted to a cross 'support bar 25, and a cover 26 closes the end of fan flue 22.

The upper section of a fuel magazine 21 is attached to the magazine extension I2 of charging section 9 by bolts 28, the shell I8 being in the joint between the extension I2 and magazine section 21. A magazine cover 29 is carried on a hinge pin 30 supported by lugs extending from the magazine 21.

Slidably fitting over the nozzle 4 of ash pit 2 is a draft air pipe section 3| which passes through the casing I8 with joint closing rings 32 surrounding it to make a tight fit with casing I8 and at the upper end of the air pipe 3l is a tight fitting e but removable cap 33 to allow access to pipe 3l.

Connected at an angle to the upper end of air pipe 3| is a vertical pipe 34 with an air pipe 35 attached to this vertical air pipe 34 and also to top of magazine section 21 so that pressure above the fuel F in magazine 21 is the same as in ash pit 2.

In the air pipe 35 is a valve that closes when the velocity ow of air from pipe 34 to the furnace is high, due to fuel leaving the magazine sufliciently to allow a free flow of air. The body 35a of this valve is shown in Fig. 1, and Fig. 4 shows the valve in detail, the body 35a having a cap 35h secured to it by bolts 35e. A light swinging check valve 35d is carried on a pivot pin 35e, the ends of which are supported in body 35a and this check has a counter balance 35j so it is almost perfectly balanced; just enough out of balance to allow it to open and remain so if the flow is light which would be the case if fuel closes the passage through the magazine. In many cases a very small air connection 35 may be used without this automatic air shut-off, more particularly where magazine cover is accurately machined and very tight fitting.

The controller parts are shown more in detail in Figs. 2 and 3, starting with the vertical air pipe 34, its elbow 35 and a connected horizontal air pipe 36 as shown in Fig. 1. A smoke pipe 31 is shown as an L in Fig. 1 for convenience and simplicity in describing the invention, but ordinarily would be a horizontal straight pipe connection attached to the side of radiator l5 shown in Fig. 1. The controller is described and referred to as shown in Figs. 2 and 3.

A bi-metallic thermostat is of U form with a copper bar 38 and a steel bar 39 riveted together with rivets 40. Around and enclosing the thermostat is a case 4| with a removable slip bottom 42, the smoke pipe 31 passing through the holes in the sides of the case. At the bottom of the case is a reinforcing ring 43 attached with rivets 44. The thermostat is supported by a bracket 45 attached to the reinforcing ring 43 with bolts 46 and the thermostat is attached to this bracket 45 with bolts 41. The thermostat hangs free in the case 4l and at its movable end is a pin 50 supported by a pair of lugs 48 attached to the thermostat with rivets 49, the pin 50 carrying the pull and push rod 5| which passes through a swivel block 52 with adjusting nuts 53 threaded on the rod on opposite sides of the block. The lower end portion of a vertical lever 55 is swung on a supporting pin 56 and carries at its lower forked end an operating pin 54 which supports the swivel block 52 and takes its motion from the thermostat. This lower end section of vertical lever 55 has a lug 51 and two screws 58 to which the lower end portion of vertical lever 59 can be attached to either side for right or left hand assembly. The pin 56 is held stationary in whatever heat range position it has been set and is carried by two vertical arms 60 0f a heat range lever 6| pivoted in a stationary support pin 62.

Extending downward from the heat range lever 6| is an arm 63 that carries an electrical double contact plug 64 with its spring 65 and insulator 66 and extending below at the lowest end is a pointer 61 that shows for what heat range this lever 6| is set. The pin 62 which carries the heat range lever 6I is supported by a stationary bracket 68 attached to the reinforcing ring 43 with bolts 69 and this bracket 68 carries in a curved channel block an insulating slide 10 which supports electrical contact slides 1| and permits adjusting of the slide 10 so that contact is made at the desired heat range, a bolt 10a securing the slide in a slot in bracket 68.

At the upper end of vertical lever 59 is a readily removable pin 12 connecting the lever to the horizontal link 13, and at the other end of link 13 is a pin 14 connecting it to a valve operating T shaped lever 15. This T lever 15 is supported and guided by its pin 16 which in turn is supported by a counter-weighted lever 11 that swivels on the stationary pin 18 mounted in lugs 83 of a double valve body 82. The counter-weighted lever has a two piece weight 19 adjustably clamped to the lever with a bolt 80, the lever moving to the dotted position 8| when the T lever 15 has one of its valve ends raised. As shown in Fig. 2, the counter-weighted lever 11 has a ring shaped boss 11a extending through and hanging clear of which is a lifter eye bolt 11b with its weight 11c which is lifted up against ring boss 11a when a hand operated chain or wire 11d is pulled up and hooked as shown in Fig. 1. Sheaves 11e are employed to direct the chain 11d toward operating side of the furnace so that a ring 11j can be hooked over its projecting pin 11g when it is desired to hold both the draft and check valves closed, a stationary eye 11h. through which the chain 11d.passes guiding and limiting the upward travel of the ring 11f induced by the weight 11c.

At the top of the furnace is the double valve body 82 attached to the smoke pipe 31 by bolts 85 which has a nozzle 84 to which the elbow 35 of Fig. 2 or the pipe 36 of Fig. 1 is slidably connected. At the left end of T lever 15 is a pin 86 that carries a draft valve stem 81 and to this stem is attached a double draft valve 88 which is almost fully balanced against the draft suctional pressure and at lower end of this double valve is a guide and stop screw 89 slidable in cross bar 90 secured to valve body 82 with screws 9|, as shown in Fig. 3.

At the right hand end of T lever 15 is a pin 92 that carries a check valve stem 93 and to the lower end of this stem is attached a check valve 94, with a lock nut 95 at the lower end of the stern. The check valve which may also be balanced as shown for the draft valve 88, passes through a loose hole in a boss 96 at the top of valve body 82 and has a heavy washer 91 which fits closely around the stem 93 and lies on boss 96 to prevent leakage.

Attached to the valve body 82 at its left end (as shown in Fig. 2) is a projecting lug 98 which carries a stationary pin 99 pivoting a hand operating lever |00 that has a stop |0| to support the lever when disengaged as shown in full lines in Fig. 2. 'Ihe upper arm of this lever |00 has a pair of lugs with pin holes |02 through which and the hole |03 in link 13 may be inserted the pin 12 when this pin is removed from the thermostat vertical lever 59 and then the hand operating lever assumes the position |04 shown by dotted lines. A pull chain |05 has an end hook |06 connected by an elastic tension spring |01 and a connecting rod |08 to the heat range lever 6|. The tension spring |01 is coiled tight upon itself and remains together while moving the valves but opens up when the draft valve is fully open therby relieving the thermostat from being sprung by any excess movement as would occur when changing the range set. When the pull chain 05 is lowered, a counterweight |09 attached by an adjusting screw ||0 to the range lever 6| exerts pressure upon the thermostat but it would be adjusted to not strain the thermostat, the chain becoming slack. A counter-weight adjustably attached with a set screw 2 to the hand lever |00 is sufficient to open the check valve 94 when the chain 05 is released. The chain |05 when attached to hand lever is indicated as |05H and the hook as |06H.

A range setting and indicating Wall plate I3 is ordinarily located on the floor above the furnace, an indicator bar Ill being attached to the pull chain |05 and having a.pointer H5 registering with the characters or numbers H8 that are identified with each heat range, a thumb nut ||1 with its bolt in the slot |I8 of the plate ||3 being actuated for securing the pointer at its selected range, the chain pulleys IIB directing the chain tothe desired position for the wall plate II3.

Current is led to the motor 24 through conductors |20 and |2| connected with a suitable 'source of current supply, the circuit being closed by the engagement of contact plug 64 carried by arm 63 of heat range lever 6| with the contact slides 1| which are adjustable for any selected heat range.

In the operation of the furnace shown the check and draft valves are closed by pulling ring 11e down and over its pin 111 before opening the fire door, thereby utilizing the full draft to carry away smoke and gases. 'I'he magazine cover 29 may be opened and additional fuel added at any time and without closing the draft valves.

It is usual in hot air furnaces to place a bypass damper in the radiator |5 connected by chain and operated by the opening and closing of the fire door so that gases can pass directly from the dome 3 to the iiue 31 when the fire door is open; but this is due to the chimney being cooled oif with the external check, and has but a very slight draft just when it is wanted the most, when adding fresh fuel. When the draft and check valves are forced shut by the operation of pull chain 11d, a limited amount of tension will be exerted upon the thermostat and any excess movement is taken up by the raising of range lever weight |09 or opening up of spring |01.

The heat range setting is established at a point away from the furnace where the heat is required and no notice need be taken of it in connection with the firing or cleaning'out of ashes.

The limit from the highest to the lowest heat range is fixed on the range setting wall plate l i3 and this full amount of travel must be utilized in the movement of the range lever 6i where connecting rod |08 is attached. To increase or decrease the amount in degrees of the change between the lowest and highest range settings, it is necessary to increase or decrease the travel of pin 56 from the two extreme positions of travel as shown dotted in Fig. 2 as 56a for the hottest range and 56h for the coldest range. To alter the travel from 56a to 56h it is necessary to change the ratio of the range lever, that is the relation of the distance from 56 to 62 to the distance from 62 to a particular hole Ela by which connecting rod |08 is attached to lever 8|.

As an illustration, it may be assumed that the thermostat pin 5D must travel 2 inches to go from 200 degrees to 560 degrees as shown in Fig. 5 under the column A and the designating number of each particular range is in column B which corresponds wih the numbers on wall plate H3 and the bracket 68.

The valve operating pin 12 must travel 1%, inches from the full open draft valve position to the full open check position.

If the ratio of vertical levers 55 and 59 is as 2 to '7 as shown in Fig. 2, then thermostat pin 50 must travel 5/ 14 inch to give the 11/4,t inch travel for the valves, these distances being shown for each of the 13 ranges as shown under C in Fig. 5.

As a further illustration, as shown in Fig. 5, when the range lever is set for No. 5 position or heat range, then the draft valve would be wide of about 60 degrees.

If all the heat ranges from 0 to 12 are either too high or too low, then the nuts 53 are adjusted accordingly. l

When the hand operated range lever |08 is connected to the valves andthe wall plate pointer lill is set at 6, then the two draft valves should be closed, the chain I 05 being altered to secure this setting.

The pointer 61 of heat range lever 6| can be made to register with the heat range numbers on bracket 68 so they are the same as that indicated on the wall plate ||3 by lengthening or shortening the pull rod |08.

When draft valve 88 is opened atmospheric air is admitted to the ash pit and when this valve is' closed vand the check valve 94 is opened the smoke pipe 31 is opened to \the ash pit through pipes 36 and 34. Thus the draft is controlled by a variation of the pressure under the grates li and by the escaping gases rather than regulating\` due to the room temperature. The operation of this device may be briey summarized as follows: When the two valves 88 and 94 that communicate with the ash pit are both closed as shown in Fig. 2, the fire would normally be burning very slowly, the only air which enters being that drawn in by leakage at the doors and joints. As the atmospheric valve 38 is gradually opened by movement of lever 15 to the right and pivoting on pin 92, valve 94 is kept closed, an additional volume of air will enter through valve 88, and through pipes 35, 34, and 3l, will flow to the ash pit, and then will pass through the fuel, and when fully open with the lever 15 at its extreme position to the right, this would produce the greatest possible draft. As the lever 15 is then moved to the left by the link 13 or its thermostatic mechanism, the air valve 88 will continue to close until both valves are again closed as in Fig. 2, and by continuing in the same direction the lever 15 will pivot on pin 88 and the smoke flue or check valve 94 will gradually be opened to the stack 31 forming afree passage through pipes 3|, 3ft and 36 from the ash pit which removes the ash pit leakage and reduces its pressure to the extent that valve llt is opened in conjunction with the amount of leakage into the ash pit. When valve 94 is fully opened and with the valve lever 15 at theextreme left, the pressure belowthe grates will thereupon tend to become substantially the same as that above them and the fire will be checked to the fullest extent.

I claim:

` 1. In a furnace having grates, ash pit and smoke pipe. the combination of a single air conduit from the ash pit to the smoke pipe, a valve between this conduit and the smoke pipe and a valve from this conduit to the atmosphere, the valves operating vertically and positioned alongside of each other and a cross operating lever pivoted to each valve, both valves closing or opening by the same directional movement of the cross operating lever so that another continuous movement of the operating lever causes one valve to close and when it is closed to open the other valve.

2. In a furnace having grates, ash pit and smoke pipe, the combination of a single air conduit from the ash pit to the smoke pipe, a valve between this conduit and the smoke pipe and a valve from this conduit to the atmosphere, the

-valves operating vertically and positionedalong- Y side of each other and a cross operating lever pivoted to each valve, both valves closing or opening by the same directional movement of the cross operating lever so that another continuous movement of the operating lever causes one valve to close and when it is closed to open the other valve and a counterweight arm pivoted in a fixed position on the smoke pipe, the end of which is attached to the cross lever to partially balance the valves.

3. In a furnace having a smoke flue and a pipe with a valved air draft connection communicating with the atmosphere, a second valve in the pipe controlling communication with the smoke flue, both of said valve connections communicate with the ash pit through said pipe, means for balancing both of said valves against the difference in pressure at each side of the valve so that but little energy is required to operate them, and means for inter-connecting the valves for opening and closing either valve while the other is closed.

4. In a furnace having grates, ash pit and smoke pipe, the combination of a single air conduit from the ash pit to the smoke pipe, a valved connection between this conduit and the smoke pipe, a separate valve controlling an opening from this conduit to the atmosphere, and a single means for operating both valves, each valve carrying a pivot for said single operating means and movable to rock thereon, and the operating means moving in one direction to close one valve and open the other, and in the other direction to close the other valve and open the first one.

5. In a furnace having a smoke flue with a pipe connection to the ash pit, meansA forming a valved opening from the atmosphere to the pipe adjacent its connection to the smoke flue, a valve between the pipe and the flue, a lever pivotally connected to the two valves, and means for operating the lever in opposite directions and causing one valve to close and become the stationary pivot for the lever to turn upon in opening the other valve.

6. A furnace having a smoke flue, grates, and an ash chamber; a pipe connecting the ash chamber with the smoke ue, a valve controlling communication in the pipe, another valve in the pipe communicating with the atmosphere, and interconnected operating means between the valve for opening one valve while the other is closed and both valves being closed in an intermediate position, thereby preventing the free flow of atmospheric air to the smoke flue.

'7. In a system of furnace draft control, comprising a smoke flue, grates, and an ash chamber, a pipe connecting the ash chamber with the smoke flue, a valve controlling communication between the smoke flue and the pipe, and a second valve controlling communication from the pipe to the atmosphere, and means for opening and closing both valves, said means including an operating connection for operating either valve when the other is closed and for closing both valves at the same time.

WILLIAM L. MORRIS. 

